The present invention concerns a method and system to exploit signals derived from linear inductive displacement sensors.
Linear inductive sensors are very commonly currently used, especially as regards angular attitude sensors and rectilinear displacement sensors. Based on the variational principle of an inductive resistor, they present the advantage of possessing extremely good linearity and excellent resolution.
Linear inductive sensors are generally preferred to other non-linear types of sensors; in fact, the linear relation, which links the output signal to displacement, allows for simpler exploitation of the signal. Moreover, their conception renders these sensors sturdy and suitable for being installed in harsh environments.
The most elementary embodiment of this type of sensor includes a primary winding and a secondary winding. The displacement of a magnetic core allows for an inductance variation which induces a secondary voltage variation.
In this type of embodiment, the signal delivered by the secondary is sensitive to variations of the primary voltage, the variation of the winding ratio according to the temperature, and to its constructional inaccuracy.
So as to minimize influence quantities, new sensors have been developed; these have been conceived on the basis of the principle relating to differential methods. The embodiment of these sensors comprises a primary winding and two secondary windings in antiphase. At this stage, it is possible to distinguish two types of sensors, namely 4-wire sensors and 6-wire sensors.
In the 6-wire sensors, the two secondary windings are independent. On the other hand, the two secondary windings of the 4-wire sensors are connected in series so as to be electrically in opposition.
Thus, it can be seen that, because of the structural differences of these sensors, the systems for exploiting the signals they generate are specific to a particular structure and may not be used for a sensor with a different structure.